Field of the Invention
This disclosure is directed to exemplary embodiments of systems, methods, techniques, processes, products and product components that can facilitate users making improved absorbance or fluorescence measurements in the field of spectroscopy with reduced (minimal) sample waste, and increased throughput, particularly in the study of biological sciences, with an objective, among others, of providing a unique, efficient solution to accurate absorbance/fluorescence measurements of liquid samples, and a reduction in equipment maintenance requirements.
Description of the Related Art
Conventionally, there are two principal methods, techniques or processes by which liquid samples are measured and analyzed.
The first conventional method involves use of a cuvette. A cuvette is a small tube generally of circular or square cross section, sealed at one end, and formed of a plastic material, glass, or fused quartz (for implementations that can involve the use of ultra-violet (UV) light). Cuvettes are designed to hold samples for spectroscopic experiments and analyses. Cuvettes are formed to have particular cross-sectional lengths, often 10 mm across, to allow for easy calculations of levels of illumination and/or coefficients of absorption.
Cuvettes are filled with liquid samples and light from a particular light source is shone through the liquid samples, the light from the particular light source often being specifically regulated through a series of intervening optics structures on a light supplying or incident side of the cuvette and correspondingly on a light collecting or recovery side of the cuvette. The involved optical elements can include, for example, integrating spheres, an intention of which is to normalize the light passed through the liquid sample from the light supplying components and recovered by light collecting components. The collected light, having passed through the liquid sample, is then passed generally to a spectrometer to evaluate absorption of the light by the liquid sample, i.e., intensity of the collected light at various wavelengths.
Cuvettes are generally not considered to be disposable items and, therefore, must be thoroughly washed between sample measurements in order to avoid contaminating the sample measurements. Further, cuvettes, and the processing of liquid sample measurements using those cuvettes, tend to waste a significant amount of a particular liquid sample.
The second method involves the spectroscopic measuring of liquid samples via a process by which microliter volume liquid samples are held by surface tension between two structural (anvil) surfaces. The anvil surfaces are highly polished, and generally include embedded optical fibers with ends finished flush with the anvil surfaces. Generally, one of the anvils is fixed, and the other of the anvils is movable to precisely control a distance between the anvils over which the absorption of the light by the liquid sample can be measured. U.S. Pat. No. 7,397,036 to Robertson et al., issued Jul. 8, 2008, describes such an exemplary measurement apparatus and method. A liquid sample is deposited on a small pedestal. The deposited liquid sample is then engaged by the anvils and essentially stretched as a liquid column supported between the anvil surfaces by surface tension in the liquid sample.
This method, which still requires contact of elements of the measuring device with the liquid sample, also requires specific cleaning of the device surfaces between sample measurements in order to avoid contaminating subsequent liquid samples leading to potentially erroneous measurements. This cleaning must be carefully undertaken in order to not affect the cleaned and polished nature of the anvils and embedded optical elements in a manner that can adversely affect liquid sample adherence retention, and/or the optical analysis.